Inverters are conventionally utilized for power supply circuits in various electric devices. An inverter converts DC or AC input power into AC output power. The amount of output power required for the inverter varies depending on the application of the inverter. In general, the desired amount of output power can be achieved by a single inverter apparatus, but the inverter apparatus needs to be individually designed for each application.
In contrast, the desired amount of output power can be achieved using an inverter system including a plurality of inverter apparatuses connected together in parallel. Here, output power from the inverter system is generated by synthesizing (superposing) output power from the plurality of inverter apparatuses. Hence, if the phases of the output power from the inverter apparatuses are synchronized and the inverter apparatuses have normalized output power characteristics, then the amount of output power from the inverter system is equal to the (unit amount of output power from the inverter apparatus)×the (total number of inverter apparatuses). Such an inverter system can be easily adapted for any of various applications simply by adjusting the total number of inverter apparatuses.
As described above, the output power from the inverter system is generated by superposition of the output power from the inverter apparatuses. Hence, a loss in the output power from the inverter system increases depending on a shift in the phase of the output power among the inverter apparatuses.